SCINTILLATION DETECTOR

Abstract: The compound scintillation detector (1) with high space and time resolution with scintillation elements (8a - 8e) are created by single crystals of ytrite-aluminium garnet both with ingredient of cerium with polished surface. The input surfaces (9a - 9e) and the bases (10a - 10e) for input of scintillation radiation are created on the opposite ends of scintillation elements (8a - 8e). The level of reflection of dielectric reflecting layers for a light emitted by scintillation elements (8a to 8e), incidenced on the reflecting layers under the angle of incidence within a range 0 to 45 DEG is higher than 50 %. The reflecting layers are created by a deposition and followed chemical-thermal processing. The bases (10a - 10e) for input of scintillation light have anti-reflecting layers on which a light is incidenced under the angle within the range for 0 to 45 DEG . The input surfaces (9a - 9e) of scintillation elements (8a - 8e) are advantageously created by dielectric interference or diffusion reflecting layer with a thickness up to 5 mu m. The effective optical separation of particular scintillation elements (8a - 8e) is advantageously realized by light-tight layer created by metal deposition. The considerably compact variant of the detector (1) is reached by a filler. The optical evaluation equipment (4) connected with the basis (10a - 10e) is created by photomultiplier with high space resolution.

Description: Scintillation Detector Field of the invention The present invention relates to the a composite scintillation detector for detection of ionizing radiation consisting of the set of horizontal scintillation elements arranged into a column matrix and having input area determined for input of detected radiation, basis for output of scintillation radiation as well as side areas created in the direction of their longitudinal axis which have dielectric reflecting layer covered by light-tight layer. Background of the invention For the time being for detection of ionizing radiation within an energy 6 keV to 1 Mev, used in positron emission tomography (PET) , computer tomography (CT) , one-photon emission tomography (SPECT) and further fields where a high space and time resolution is reguired, the scintillation detectors on the basis of single crystal BGO, Na:I:Tl and CsI:Tl are used. Physical and chemical properties of these materials do not give a possibility to construct detectors with cross-section lower than 1 mm 2 . All these scintillation materials have relatively long decay time, for example in case of very often used scintillator BGO the decay time is 280 ns which is very disadvantageous for the mentioned applications. The single crystals Nal.Tl and CsI:Tl are very hydroscopic and require capsizing which does not enable to arrange crystals. The known crystals are equipped by diffusion reflecting layer and they are optically separated in such a way that the minimal distance of two neighbouring crystals is greater than 0,5 mm which in the best cases enables to perform measurement with space resolution higher than 2 mm. A composite scintillation detector is known from German DE 41 07 264 Al. The material of scintillation elements of known detector is represented by sintrated ceramic oxide of rare earth, or mixture Cd 2 0 3 and Eu 2 0 3 with the rest Y 2 0 3/ or BGdO, Csl, CdW0 4 , BiGe and etc. Between the particular scintillation elements in the direction parallel with the direction of input radiation there are diffusions reflecting layers with thickness of 50 μm on the basis Ti0 2 Between the neighbouring reflecting layers there is a collimination layer determined for optical and energetic separation of particular scintillation elements, or for collimination of input of gamma radiation. On the interface of scintillation elements in the direction perpendicular to the direction of input radiation the passive energetic filters are created giving a possibility to determine an energy of input radiation. To ensure efficiency of filtration it is necessary that the filtration layers must be more than 10 μm thick. The incidence of input radiation on detector is realized perpendicularly to longitudinal dimension of scintillation elements. As equipment for scanning of scintillation radiation a known detector of diodes of type PN or PIN, or elements CCD is used. The disadvantage of known detector is its low ability of space resolution conditioned by considerable whole thickness of used diffusion reflecting and climate layers on the one side and reflecting and filtration layers on the second side. The known detector is not suitable for usage in the fields requiring high space and time resolution. The CCD elements used for scanning of scintillation light does not enable to scan time component of impulses of scintillation radiation because signals are evaluated periodically after a certain time of integration. From European patent application EP 0 437 051 A2 a scintillation detector is known the scintillation elements of which are represented by crystals BGO partially provided with burnished interfaces. This burnished interfaces are combined with roughed regions having other properties from standpoint of radiation of a light, so there is transfer of scintillation radiation between neighbouring scintillation elements. The extent of transformation of a light can be changed randomly by the change of structure of interface. After evaluation of scintillation radiation this detector uses a larger number of photo multipliers assigned to particular parts of scintillation field determined by output areas of crystals. The consequences of transferring of scintillation radiation between neighbouring scintillation elements which are not separated by light-tight layer are represented by optical losses decreasing space and time resolution of detector. The Czechoslovak author's certificate No. 263 791 finally describes scintillation detector of low energy radiation beta and electrons consisting of one single crystal of aluminiun-ytrite garnet activated by cerium, or aluminium- ytrite perovskite activated by cerium in the form of both- side polished plate, or truncated cone having polished surface except of basis serving for output of a light. On the surface of this detector the dielectric reflecting layer is created covered on the surface by electrically conducted layer determined for input of a radiation. Disclosure of the invention The objective of the invention is to design composite scintillation detector of the type described in the introductory part of this application, with high space and time resolution offering colli ated scintillation light which is possible to be scanned without special evaluation equipment available on the market without spending of high expenses. The material of used scintillation elements should be workable and should have good chemical resistance and very short time of decay. The used evaluation equipment must enable to perform separated scanning of each impulses of scintillation radiation as well as determination of its amplitude and position during the scanning of time component of impulses. According to the invention this objective is reached by the fact that scintillation elements are created by single crystals of ytrite-aluminium garnet with ingredient of cerium (YAG:CE, or Y 3 AL 15 0 12 :CE) with polished surface when input surface and basis for input of scintillation radiation are created on the opposite ends of scintillation elements. The second solution of the mentioned task is based on the fact that scintillation elements are created by single crystals of ytrite-aluminium perovskite with ingredient of cerium (YAP:CE or YA10 3 :Ce) with polished surface when the input surface and basis for output of scintillation radiation are created on the opposite ends of scintillation elements. According to the further advantageous realization of the subject of the invention the value of reflection of dielectric reflecting layers for a light emitted by scintillation elements with wave lengths determined by half-width of their emission with the angle of incidence on reflecting layer within the range 0 to 45° is higher than 50%. The reflecting layers are created by multiplied deposition with followed chemical-thermal processing as interference reflecting layer. This measures give a possibility to create very thin reflecting layers (several micrometers thick) where the rule of reflection is valid. Chemical-thermal processing improves wave dependence of a reflection, or integral reflection of layers by increasing of half-width of a reflection (FWHM) depending on wave length of scintillation light. The interference layers have lower angle dependence of a reflection, i.e. they are not defined only for perpendicular incidence of a light. The further increase of luminescent efficiency was reached in such a way that the bases for output of scintillation light have anti reflecting layers for a light emitted by scintillation elements with wave lengths determined by half-width of their emission and incidencing on the reflecting layer with the angle of incidence in the range 0 to 45°. The usage of anti reflecting layers decreases loses of reflections on the output of scintillators which are determined by high index of breaking of crystals YAG and YAP and a possibility to use optical fillers. The thin anti reflecting layers with required properties were obtained by multiplied deposition with followed chemical-thermal processing. It is very advantageous when output surfaces of scintillation elements have also dielectric interference reflection layer. The thickness of dielectric interference reflecting layers is not bigger than 5 μm. Input surfaces can also have dielectric diffusions reflecting layer. In this case there is not a deterioration of space resolution and input surfaces of crystals are efficiently protected against mechanical damage. A very affective mutual optical separation of particular scintillation elements was reached in such a way that light-tight layer consists of metal deposition by some of metals Al, W, Mo, Fe, Cr, Ni, Au, Ag, Cu with a thickness within the range 0,05 to 1 μm with advantages within the range 0,08 to 0,15 μm. Specially compact realization of the detector according to the invention was reached in such a way that between the side surfaces of particular scintillation elements there is modified layer of a filler in such a way that the distance between the neighbouring scintillation elements is not greater than 0,01 mm when the thickness of the filler layer is not greater than 5 μm. The size of input area, or basis for output of scintillation radiation is 0,01 to 10 mm 2 with advantage 0,06 to 1 mm 2 . From a standpoint of evaluation of scintillation light emitted by scintillation elements in the detector according to the invention the optical evaluation equipment is connected with the basis for output of scintillation light. This optical evaluation equipment changes scintillation light into electric signals. This is very advantageous when this evaluation equipment is connected with the basis by optical filler with breaking index n the value of which is within the range 1,4 to 1,6. Such arrangement enables to realize a transfer of scintillation light into the evaluation equipment with minimal optical losses. The optical evaluation equipment is represented by photo multiplier with high space resolution which enables to perform an efficient suppression of a noise of the system by usage of time component of impulses. The further possibility is a usage of photo-diode field with a low level of noise for evaluation of scintillation radiation. According to the invention the excellent resolution of the detector is reached in such cases when single crystals of ytrite-aluminium garnet with ingredient of cerium are created by stechio etric compound 0,05 to 2,0 mol. % Cr 2 0 3 , 62,5 mol. % A1 2 0 3 and the rest of Y 2 0 3 , or in case that the single crystals ytrite-aluminium perovskite with ingredient are created by stechiometric compound 0,05 to 2,0 mol % Ce 2 0 3 , 50,0 mol. % A1 2 0 3 and the rest of Y0 3 . The mentioned extent of usage of cerium optimizes luminescent efficiency. The physical properties of the mentioned crystals enable to detect X-ray radiation as well as beta and gamma radiation which is very suitable for usage of detector in computer tomography as indicated in the invention. Summary of the pictures in the drawing The invention will be explained in the next text in connection with attached pictures as follows: Pic.l.: Composite scintillation detector according to the invention in isometric view Pic.2.: Section A-A according to the Pic.l, partially broken Pic.3.: Graphical viewing of results of a measurement realized with detector according to the invention. The compound scintillation detector 1. indicated in the Pic.l consists of 25 longitudinal scintillation elements 8a, 8b, 8c, 8d, 8e arranged into the quarter matrix 5 5 in such a way that they are attached by their side surfaces lla-1, lla-2. llb-1. llb-2. llc-1. llc-2. lld-1... which are created in the direction of their horizontal axis. To simplify the matter only the first row of scintillation elements of mentioned matrix is indicated. The particular scintillation elements 8a ... 8e are created by single crystals of ytrite-alluminium garnet (YAG:Ce), or by ytrite-alluminium perovskite with ingredient of cerium (YAP:CE) created by stechiometric compounds 0,05 to 2,0 mol. % Ce 2 0 3 , 62,5 mol. % A1 2 0 3 and the rest of Y 2 0 3 or 0,05 to 2,0 mol % Ce 2 0 3 , 50,0 mol. % A1 2 0 3 and the rest of Y 2 0 3 . On the upper end of particular scintillation elements 8a ... 8e there are input surfaces 9a. 9b. 9c, 9d. 9e for input of detected ionizing radiation incidencing on the detector 1 in the direction of incidence which is indicated by the arrow 5_. The basis for output of scintillation light created by the bases 10a, 10b. 10c, lOd, lOe on the opposite ends of scintillation elements, the optical scanning equipment _____ is connected which changes scintillation light emitted by scintillation elements into electric impulses schematically indicated by the arrow 6 . and created advantageously by positionally sensitive photo multiplier with high space resolution connected through A/D converter 3 . to evaluation equipment, or processor 4_, the input of which is represented by electric impulses 1_. The connection of the basis 10a. lOb. 10c, lOd, lOe ... of the detector 1 with photo multiplier 2 . is advantageously connected with optical filler with breaking index n the value of which is within the range 1,4 to 1,6. The partial section, indicated in the Pic.2, shows that particular scintillation elements 8a, ... 8d are provided with dielectric interference reflecting layers 12a-2. 12b- 1, 12b-2. 12c-l. 12C-2. 12d-l or 15a. 15b. 15c. 15d. 15e on their side surfaces lla-2, llb-1 ... lld-1 connected mutually as well as on their input surfaces 9a, 9b, 9c, 9d. These reflecting layers are created by several gradually deposited layers of suitable dielectric, or Si0 2 , Ti0 2 , Y 2 0 3 , Zr0 2 and then treated by chemical-thermal processing which considerable improves wave dependence of reached reflection. Before a treatment of dielectric reflection layers the surface of particular crystals was polished when the thickness of reflecting layers is not greater than 5 μm. The values of reflection of interference reflection layers 12a-2. 12b-l. 12b-2, 12c-l, 12d-l ... are considerable higher than 50% for scintillation lights emitted by single crystals 8a, 8b, 8c, 8d with wave lengths determined by half-width of their emission (FWHM) and incidencing on these layers under the angle of incidence within the range 0 to 45°. At the same time it is possible to provide input surfaces 9a, 9b, 9c, 9d of scintillation elements 8a. 8b, 8c, 8d by difussion reflection layer. For optical separation of particular of particular scintillation elements 8a, 8b, 8c, 8d the light-tight layers 13a-2, 13b-l, 13b-2, 13c-l. 13c-2 , 13d-l .... are used which are created by metal deposition with thickness within 0,05 to 1 μm, advantageously within the range 0,08 to 0,15 μm. The suitable material for creation of light- tight layers are aluminium, tungsten, molybdenum, iron, chrome, nickel, gold, silver or copper. At the same time it is advantageous when input surfaces 9a, 9b, 9c. 9d of particular scintillation elements 8a, 8b, 8c. 8d are provided with light-tight layer 18a, 18b, 18c, 18d. The creation of light-tight layer on the input surface of detection unit enables to use it outside light-tightly closed equipment. For mutual connection of particular scintillation elements 8a. 8b, 8c. 8d the particular thin layers 17a-b, 17b-c, 17c-d of filler are used the thickness of which is not greater than 5 μm. The whole distance between the particular single crystals, arranged into a regular matrix, is not greater than 0,01 mm with the above indicated selection of thickness of the particular layers. From the Pic.2 it is evident that the bases 10a. 10b. 10c. lOd of the particular scintillation elements 8a, 8b, 8c. 8d for output of scintillation light are provided with anti reflecting layers 14a. 14b. 14c and 14d for a light emitted by scintillation elements 8a, 8b, 8c. 8d with wave lengths determined by half-width of their emission and incidenced on anti reflecting layers 14a. 14b, 14c. 14d under the angle of incidence within the range 0 to 45°. Similarly as in case of above mentioned dielectric interference reflecting layers the anti reflecting layers 14a, 14b, 14c, 14d are advantageously created by multiple deposition by suitable materials e.g. Si0 2 , Ti0 2 , Y 2 0 3 , Zr0 2 after which there is chemical-thermal processing. For the connection of photo multiplier 2. with detector 1 according to the invention the optical filler JL6. is used with breaking index n laying within the range 1,4 to 1,6. Examples of realization of the invention Example 1: The mentioned detector according to the invention was used for measurement of the results which are indicated in the Pic.3. When measuring the column matrix with the dimension 20 x 17 x 7 mm was used created by single crystals of ytrite-alluminium perovskite with ingredient of cerium (YAP:CE, 1,0 mol. % Cr 2 0 3 ) with dimensions 0,6 x 0,6 x 7 mm. For optical scanning equipment the position sensitive photo multiplier of the company HAMAMATSU R 2846 was used with great space resolution. The detector was irradiated by collimative radiation gamma ("Tc, 140 keV) on two places distanced by 1,8 mm (four detecting elements) through collimator with a diameter 0,2 and 0,4 mm. Both peaks of curves in the picture 3 correspond to the distance of centers of input surfaces of the first and fourth radiated single crystal equals to 1,8 mm, or to the value of 10 channels of evaluating equipment with sensitivity of one channel equals to 1,18 mm. The space resolution of measured system (FWHM) was 4 x 0,18 mm = 0,72 mm. Example 2: From a single crystal of ytrite-alluminium garnet with ingredient of cerium (YAG:CE) the longitudinal scintillation elements were prepared with a quarter basis 0,5 mm long and length 25 mm the surface of which was polished. The surface areas of particular scintillation elements were provided with dielectric interference reflecting layer with the value of reflexivity of R = 92% for a light emitted by scintillation elements with maximum wave length λ = 550 nm. Then the reflecting layer was covered by aluminium deposition with a thickness about 120 nm. Such prepared scintillation elements were arranged into the quarter matrix 5 x 5 elements which are indicated in the Pic.l, and mutually connected by epoxide filler in such a way that the whole distance between the neighbouring scintillation elements was about 0,008 mm. This arrangement creates composite detector with the dimensions 2,53 x 2,53 x 5 mm. The basis for output of scintillation light was polished and then connected by a layer of optical fitting with photo multiplier with high space resolution higher than 0,3 mm. When measuring in the collimated beam of X-ray radiation with maximal energy of 145 eV the space resolution of detector greater than 0,6 mm was reached. Example 3: From the single crystals of ytrite-alluminium perovskite with ingredient of cerium (YAP:CE) the longitudinal scintillation elements were prepared with a side of quarter basis of 0,3 mm and 25 mm long the surface of which was polished. The surface areas of the particular scintillation elements were equipped with dielectric interference reflecting layer processed by chemical-thermal treatment with the value of reflection R = 93% for a light emitted by scintillation elements with maximum wave length λ = 370 nm. Then the reflecting layer was covered by molybdenum deposition with a thickness about 120 nm. Such prepared longitudinal scintillation elements were arranged into the quarter matrix 10 x 10 elements and mutually connected by epoxide filler. This arrangement creates composite detector with the dimensions 3,09 x 3,09 x 25 mm. The basis for output of scintillation light was polished and then connected by a layer of optical fitting with breaking index of n = 1,45 with photo multiplier with high space resolution higher than 0,3 mm. When measuring in the collimated beam of X-ray radiation with maximal energy of 512 eV the space resolution of detector greater than 0,5 mm was reached. The usage of composite scintillation detector according to the invention can be used mainly in nuclear and experimental medicine and non-destructive defectoscopy.

Claims: CLAIMS 1. Scintillation detector for detection of ionizing radiation consisting of the set of longitudinal scintillation elements arranged into the column matrix and having input surface determined for input of detected radiation, basis for output of scintillation light as well as side surfaces created in the direction of their longitudinal axis which are provided with dielectric reflection layer covered by light-tight layer, characterized by the fact, that the scintillation elements (8a-8e; ...) are created by single crystals of ytrite-alluminium garnet with ingredient of cerium (YAG:CE, or Y 3 ALι 5 0 12 :Ce) with polished surface when input surface (9a-0e; ...) and basis (lOa-lOe; ...) for input of scintillation radiation are created on the opposite ends of scintillation elements. 2. The scintillation detector for detection of ionizing radiation consisting of the set of longitudinal scintillation elements arranged into the column matrix and having input surface determined for input of detected radiation, basis for output of scintillation light as well as side surfaces created in the direction of their longitudinal axis which are provided with dielectric reflection layer covered by light-tight layer, characterized by the fact, that scintillation elements (8a-8e; ...) are created by single crystals of ytrite-alluminium perovskite with ingredient of cerium (YAP:CE or YA10 3 :Ce) with polished surface when the input surface (9a-9e; ...) and basis (lOa-lOe; ...) for output of scintillation radiation are created on the opposite ends of scintillation elements (8a-8e; ...). SUBSTITUTESHEET 3. The scintillation detector according to claim 1 or 2, wherein the reflecting layers (12a-2, 12b-l, 12b-2, 12c-l, 12c-2, 12d-l) are created as interference reflecting layers by multiplied deposition and followed chemical-thermal processing. 4. The scintillation detector according to claim 1 or 2, wherein the values of reflection of interference reflecting layers (12a-2, 12b-l, 12b-2, 12c-l, l2c-2, 12d-l) are higher than 50% for a light emitted by single crystals (8a-8e; ...) with wave lengths determined by half-width of their emission and incidencing on these layers (12a-2, 12b-l, 12b-2, 12c- 1, 12c-2, 12d-l) under the angle of incidence within the range 0 to 45°. 5. The scintillation detector according to claim 4, wherein the reflection layers (12a-2, 12b-l, 12b-2, 12c-l, 12c-2, 12d-l) are created as interference reflecting layers by multiplied deposition with followed chemical-thermal processing. 6. The scintillation detector according to claims 1 to 5, wherein between the side surfaces (lla-1, lla-2, llb-1, llb-2, llc-1, llc-2, lld-l...) of particular scintillation elements (8a, 8b, 8c, 8d) there is modified layer (17a-b, 17b-c, 17c-d) of filler in such a way that the distance between the neighbouring scintillation elements (8a, 8b, 8c, 8d) is not greater than 0,01 mm. 7. The scintillation detector according to claims 1 to 6, wherein the bases (lOa-lOe; ...) for output of scintillation light are provided with anti reflecting SUBSTITUTE SHEET layer (14a, 14b, 14c, 14d) for a light emitted by scintillation elements (8a, 8b, 8c, 8d) with wave lengths determined by half-width of their emission and incidencing on anti reflecting layer (14a, 14b, 14c, 14d) under the angle of incidence within the range 0 to 45°. 8. The scintillation detector according to claims 1 to 7, wherein the anti reflecting layers (14a, 14b, 14c, 14d) are created by multiplied deposition with followed chemical-thermal processing. 9. The scintillation detector according to claims 1 to 8, wherein the input surface (9a, 9b, 9c, 9d) of scintillation elements (8a, 8b, 8c, 8d) is provided with dielectric interference reflecting layer (15a, 15b, 15c, 15d) . 10. The scintillation detector according to claims 1 to 8, wherein the input surface (9a, 9b, 9c, 9d) of scintillation elements (8a, 8b, 8c, 8d) is provided with dielectric diffusion reflecting layer. 11. The scintillation detector according to claim 9 or 10, wherein the input surface (9a, 9b, 9c, 9d) of scintillation elements (8a, 8b, 8c, 8d) is provided with light-tight layer (18a, 18b, 18c, 18d.) . 12. The scintillation detector according to the claim 6, I wherein the thickness of layer (17a-b, 17b-c, I7c-d) of the filler is not greater than 5 μm. 13. The scintillation detector according to claims 1 to 7 and 8 or 9 wherein the thickness of dielectric SUBSTITUTE SHEET interference reflecting layers (12a-2, 12b-l, 12b-2, 12c-l, 12c-2, 12d-l, 15a-15d) is not greater than 5 μm. 14. The scintillation detector according to claims 1 to 13, wherein the light-tight layer (12a-2, 12b-l, 12b- 2, 12c-l, 12c-2, 12d-l) is created by metal deposition of some of metals Al, W, Mo, Fe, Cr, Ni, Au, Ag, Cu with a thickness within the range 0,05 to 1 μm. 15. The scintillation detector according to claim 14, wherein the value of thickness of metal deposition is within the range 0,08 to 0,15 μm. 16. The scintillation detector according to claims 1 to 15, wherein the size of input surface (9a-9e; ...) or the basis (lOa-lOe; ...) for output of scintillation light is 0,01 to 10 mm 2 . 17. The scintillation detector according to claim 16, wherein the size of input surface (9a-9e; ...) or the basis (lOa-lOe; ...) for output of scintillation radiation is 0,06 to 1 mm 2 . 18. The scintillation detector according to some of previous claims on the base of which for output of scintillation length the optical evaluation equipment is used which changes scintillation light into electric impulses, wherein the optical evaluation equipment (2) is connected with the basis (10) by optical filler (16) with breaking index n the value of which is in the range 1,4 to 1,6. 19. The scintillation detector according to claim 18, SUBSTITUTE SHEET wherein the optical evaluation equipment (2) is created by photo multiplier with high space resolution. 20. The scintillation detector according to claim 18, wherein the optical evaluation equipment (2) is created by a field of photo diodes. 21. The scintillation detector according to claim 1, wherein the single crystals of ytrite-alluminium garnet with ingredient of cerium (YAG:CE) are created by stechiometric compounds 0,05 to 2,0 mol. % Ce 2 0 3 , 62,5 mol. % A1 2 0 3 and the rest of Y 2 0 3 . 22. The scintillation detector according to claim 2, wherein the single crystals of ytrite-alluminium perovskite with ingredient of cerium (YAP:CE or YAl0 3 :Ce) are created by stechiometric compound 0,05 to 2,0 mol. % Cr 2 0 3 , 62,5 mol. % Al 2 0 3 and the rest of Y 2 o 3 . 23. The ' scintillation detector according to some of previous claims, characterized by the fact, that the detected ionizing radiation is X-ray radiation. 24. The scintillation detector according to some of previous claims 1 to 22, wherein the detected ionizing radiation is beta radiation. 25. The scintillation detector according to some of previous claims 1 to 22, wherein the detected ionizing radiation is gamma radiation. SUBSTITUTE SHEET

Inventors: BLAZEK KAREL, DE NOTARISTEFANI FRANCESCO, MALY PETR, BLAZEK, KAREL, DE NOTARISTEFANI, FRANCESCO, MALY, PETR
Applicants: BLAZEK KAREL, MALY PETR, NOTARISTEFANI FRANCESCO DE, PRECIOSA A S, BLAZEK, KAREL, DE NOTARISTEFANI, FRANCESCO, MALY, PETR, PRECIOSA A.S.
Application year: 1994
Main classification: G01T1
IPC codes: G01T1